Syntheses and Unusual Segregated−Alternated Hybrid Stacking Structure of Hydrogen-Bonded Charge-Transfer Complexes Composed of Bis[2,3-pyridinedithiolate]metal Complexes

We report the syntheses of new planar electron donor inorganic molecules [bis(2,3-pyridinedithiolate)metal(II)];
[MII(Hpydt)2] (M = Ni(1), Pd(2), Pt(3)) and their anions; [MII(pydt)2]2- (M = Ni(4), Pd(5)), which are equipped with
both a highly lying highest occupied molecular orbital (HOMO) perpendicular to the plane and hydrogen-bonding
capability in the plane. In addition, we present two novel hydrogen-bonded charge-transfer (HBCT) complexes,
[M(Hpydt)2]TCNQ (M = Ni, Pd), with 7,7,8,8-tetracyanoquinodimethane (TCNQ). All the neutral and ionic inorganic
molecules and the HBCT complexes were successfully characterized by single-crystal X-ray crystallography. The
HBCT complexes show an unusual segregated−alternated hybrid stacking structure in which each component
interacts parallel to the stacks with neighboring donors and acceptors. Furthermore, the structural network is expanded
as a result of a one-dimensional hydrogen-bonding chain formed between donors and acceptors perpendicular to
the stacking direction. The theoretical electronic structures of the HBCT complexes are also reported.